This invention relates generally to turbine engines and, more particularly, to methods and apparatus for constructing turbine bucket cutter teeth.
At least some known turbine engines include at least one stator assembly and at least one rotor assembly that includes at least one row of circumferentially-spaced turbine blades or buckets. The blades extend radially outward from a platform to a tip. A plurality of static shrouds coupled within the stator assembly abut together to define a flow path that extends substantially circumferentially around the rotor assembly. A seal may be provided at the tip of the buckets to facilitate enhancing turbine efficiency and performance.
At least some known rotor assemblies include a tip shroud formed on the outboard end of each bucket. Known tip shrouds each include a shelf and a sealing rail. A honeycomb structure may surround the tip shroud, and in such embodiments, the sealing rail may include one or more cutter teeth that cut through some of the honeycomb material to establish a tip clearance. Minimizing tip clearances facilitates improving turbine performance, but the tip clearance must still be sized large enough to facilitate rub-free engine operation through the range of available engine operating conditions.
Known tip shroud areas, may be vulnerable to creep damage arising when the cutter tooth mass is exposed to high operating temperatures and rotational stresses that may be present during engine operation. To facilitate reducing creep issues, at least some turbine assemblies, centrally locate cutter teeth relative to each bucket. However, because the cutter teeth serve no purpose after the honeycomb structures have been cut through and the tip clearances established, it would be advantageous if the cutter teeth could be removed after the initial hours of operation of the engine. However, with known rotor assemblies, to remove the cutter teeth, the engine would have to be shut down and the rotor assembly removed to enable a user to remove the cutter teeth from the engines.